drivers/cpufreq/cpufreq_stats.c

   1 /*
   2  *  drivers/cpufreq/cpufreq_stats.c
   3  *
   4  *  Copyright (C) 2003-2004 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
   5  *  (C) 2004 Zou Nan hai <nanhai.zou@intel.com>.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/cpu.h>
  13 #include <linux/cpufreq.h>
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16 #include <linux/cputime.h>
  17
  18 static spinlock_t cpufreq_stats_lock;
  19
  20 struct cpufreq_stats {
  21         unsigned int cpu;
  22         unsigned int total_trans;
  23         unsigned long long last_time;
  24         unsigned int max_state;
  25         unsigned int state_num;
  26         unsigned int last_index;
  27         u64 *time_in_state;
  28         unsigned int *freq_table;
  29 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  30         unsigned int *trans_table;
  31 #endif
  32 };
  33
  34 static int cpufreq_stats_update(struct cpufreq_stats *stats)
  35 {
  36         unsigned long long cur_time = get_jiffies_64();
  37
  38         spin_lock(&cpufreq_stats_lock);
  39         if (stats->time_in_state)
  40                 stats->time_in_state[stats->last_index] +=
  41                         cur_time - stats->last_time;
  42         stats->last_time = cur_time;
  43         spin_unlock(&cpufreq_stats_lock);
  44         return 0;
  45 }
  46
  47 static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
  48 {
  49         return sprintf(buf, "%d\n", policy->stats->total_trans);
  50 }
  51
  52 static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
  53 {
  54         struct cpufreq_stats *stats = policy->stats;
  55         ssize_t len = 0;
  56         int i;
  57
  58         cpufreq_stats_update(stats);
  59         for (i = 0; i < stats->state_num; i++) {
  60                 len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i],
  61                         (unsigned long long)
  62                         jiffies_64_to_clock_t(stats->time_in_state[i]));
  63         }
  64         return len;
  65 }
  66
  67 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  68 static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
  69 {
  70         struct cpufreq_stats *stats = policy->stats;
  71         ssize_t len = 0;
  72         int i, j;
  73
  74         cpufreq_stats_update(stats);
  75         len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
  76         len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
  77         for (i = 0; i < stats->state_num; i++) {
  78                 if (len >= PAGE_SIZE)
  79                         break;
  80                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
  81                                 stats->freq_table[i]);
  82         }
  83         if (len >= PAGE_SIZE)
  84                 return PAGE_SIZE;
  85
  86         len += snprintf(buf + len, PAGE_SIZE - len, "\n");
  87
  88         for (i = 0; i < stats->state_num; i++) {
  89                 if (len >= PAGE_SIZE)
  90                         break;
  91
  92                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
  93                                 stats->freq_table[i]);
  94
  95                 for (j = 0; j < stats->state_num; j++) {
  96                         if (len >= PAGE_SIZE)
  97                                 break;
  98                         len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
  99                                         stats->trans_table[i*stats->max_state+j]);
 100                 }
 101                 if (len >= PAGE_SIZE)
 102                         break;
 103                 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 104         }
 105         if (len >= PAGE_SIZE)
 106                 return PAGE_SIZE;
 107         return len;
 108 }
 109 cpufreq_freq_attr_ro(trans_table);
 110 #endif
 111
 112 cpufreq_freq_attr_ro(total_trans);
 113 cpufreq_freq_attr_ro(time_in_state);
 114
 115 static struct attribute *default_attrs[] = {
 116         &total_trans.attr,
 117         &time_in_state.attr,
 118 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 119         &trans_table.attr,
 120 #endif
 121         NULL
 122 };
 123 static struct attribute_group stats_attr_group = {
 124         .attrs = default_attrs,
 125         .name = "stats"
 126 };
 127
 128 static int freq_table_get_index(struct cpufreq_stats *stats, unsigned int freq)
 129 {
 130         int index;
 131         for (index = 0; index < stats->max_state; index++)
 132                 if (stats->freq_table[index] == freq)
 133                         return index;
 134         return -1;
 135 }
 136
 137 static void __cpufreq_stats_free_table(struct cpufreq_policy *policy)
 138 {
 139         struct cpufreq_stats *stats = policy->stats;
 140
 141         /* Already freed */
 142         if (!stats)
 143                 return;
 144
 145         pr_debug("%s: Free stats table\n", __func__);
 146
 147         sysfs_remove_group(&policy->kobj, &stats_attr_group);
 148         kfree(stats->time_in_state);
 149         kfree(stats);
 150         policy->stats = NULL;
 151 }
 152
 153 static void cpufreq_stats_free_table(unsigned int cpu)
 154 {
 155         struct cpufreq_policy *policy;
 156
 157         policy = cpufreq_cpu_get(cpu);
 158         if (!policy)
 159                 return;
 160
 161         __cpufreq_stats_free_table(policy);
 162
 163         cpufreq_cpu_put(policy);
 164 }
 165
 166 static int __cpufreq_stats_create_table(struct cpufreq_policy *policy)
 167 {
 168         unsigned int i, count = 0, ret = 0;
 169         struct cpufreq_stats *stats;
 170         unsigned int alloc_size;
 171         unsigned int cpu = policy->cpu;
 172         struct cpufreq_frequency_table *pos, *table;
 173
 174         table = cpufreq_frequency_get_table(cpu);
 175         if (unlikely(!table))
 176                 return 0;
 177
 178         /* stats already initialized */
 179         if (policy->stats)
 180                 return -EEXIST;
 181
 182         stats = kzalloc(sizeof(*stats), GFP_KERNEL);
 183         if ((stats) == NULL)
 184                 return -ENOMEM;
 185
 186         ret = sysfs_create_group(&policy->kobj, &stats_attr_group);
 187         if (ret)
 188                 goto error_out;
 189
 190         stats->cpu = cpu;
 191         policy->stats = stats;
 192
 193         cpufreq_for_each_valid_entry(pos, table)
 194                 count++;
 195
 196         alloc_size = count * sizeof(int) + count * sizeof(u64);
 197
 198 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 199         alloc_size += count * count * sizeof(int);
 200 #endif
 201         stats->max_state = count;
 202         stats->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
 203         if (!stats->time_in_state) {
 204                 ret = -ENOMEM;
 205                 goto error_alloc;
 206         }
 207         stats->freq_table = (unsigned int *)(stats->time_in_state + count);
 208
 209 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 210         stats->trans_table = stats->freq_table + count;
 211 #endif
 212         i = 0;
 213         cpufreq_for_each_valid_entry(pos, table)
 214                 if (freq_table_get_index(stats, pos->frequency) == -1)
 215                         stats->freq_table[i++] = pos->frequency;
 216         stats->state_num = i;
 217         spin_lock(&cpufreq_stats_lock);
 218         stats->last_time = get_jiffies_64();
 219         stats->last_index = freq_table_get_index(stats, policy->cur);
 220         spin_unlock(&cpufreq_stats_lock);
 221         return 0;
 222 error_alloc:
 223         sysfs_remove_group(&policy->kobj, &stats_attr_group);
 224 error_out:
 225         kfree(stats);
 226         policy->stats = NULL;
 227         return ret;
 228 }
 229
 230 static void cpufreq_stats_create_table(unsigned int cpu)
 231 {
 232         struct cpufreq_policy *policy;
 233
 234         /*
 235          * "likely(!policy)" because normally cpufreq_stats will be registered
 236          * before cpufreq driver
 237          */
 238         policy = cpufreq_cpu_get(cpu);
 239         if (likely(!policy))
 240                 return;
 241
 242         __cpufreq_stats_create_table(policy);
 243
 244         cpufreq_cpu_put(policy);
 245 }
 246
 247 static void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy)
 248 {
 249         policy->stats->cpu = policy->cpu;
 250 }
 251
 252 static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
 253                 unsigned long val, void *data)
 254 {
 255         int ret = 0;
 256         struct cpufreq_policy *policy = data;
 257
 258         if (val == CPUFREQ_UPDATE_POLICY_CPU) {
 259                 cpufreq_stats_update_policy_cpu(policy);
 260                 return 0;
 261         }
 262
 263         if (val == CPUFREQ_CREATE_POLICY)
 264                 ret = __cpufreq_stats_create_table(policy);
 265         else if (val == CPUFREQ_REMOVE_POLICY)
 266                 __cpufreq_stats_free_table(policy);
 267
 268         return ret;
 269 }
 270
 271 static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
 272                 unsigned long val, void *data)
 273 {
 274         struct cpufreq_freqs *freq = data;
 275         struct cpufreq_policy *policy = cpufreq_cpu_get(freq->cpu);
 276         struct cpufreq_stats *stats;
 277         int old_index, new_index;
 278
 279         if (!policy) {
 280                 pr_err("%s: No policy found\n", __func__);
 281                 return 0;
 282         }
 283
 284         if (val != CPUFREQ_POSTCHANGE)
 285                 goto put_policy;
 286
 287         if (!policy->stats) {
 288                 pr_debug("%s: No stats found\n", __func__);
 289                 goto put_policy;
 290         }
 291
 292         stats = policy->stats;
 293
 294         old_index = stats->last_index;
 295         new_index = freq_table_get_index(stats, freq->new);
 296
 297         /* We can't do stats->time_in_state[-1]= .. */
 298         if (old_index == -1 || new_index == -1)
 299                 goto put_policy;
 300
 301         cpufreq_stats_update(stats);
 302
 303         if (old_index == new_index)
 304                 goto put_policy;
 305
 306         spin_lock(&cpufreq_stats_lock);
 307         stats->last_index = new_index;
 308 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 309         stats->trans_table[old_index * stats->max_state + new_index]++;
 310 #endif
 311         stats->total_trans++;
 312         spin_unlock(&cpufreq_stats_lock);
 313
 314 put_policy:
 315         cpufreq_cpu_put(policy);
 316         return 0;
 317 }
 318
 319 static struct notifier_block notifier_policy_block = {
 320         .notifier_call = cpufreq_stat_notifier_policy
 321 };
 322
 323 static struct notifier_block notifier_trans_block = {
 324         .notifier_call = cpufreq_stat_notifier_trans
 325 };
 326
 327 static int __init cpufreq_stats_init(void)
 328 {
 329         int ret;
 330         unsigned int cpu;
 331
 332         spin_lock_init(&cpufreq_stats_lock);
 333         ret = cpufreq_register_notifier(&notifier_policy_block,
 334                                 CPUFREQ_POLICY_NOTIFIER);
 335         if (ret)
 336                 return ret;
 337
 338         for_each_online_cpu(cpu)
 339                 cpufreq_stats_create_table(cpu);
 340
 341         ret = cpufreq_register_notifier(&notifier_trans_block,
 342                                 CPUFREQ_TRANSITION_NOTIFIER);
 343         if (ret) {
 344                 cpufreq_unregister_notifier(&notifier_policy_block,
 345                                 CPUFREQ_POLICY_NOTIFIER);
 346                 for_each_online_cpu(cpu)
 347                         cpufreq_stats_free_table(cpu);
 348                 return ret;
 349         }
 350
 351         return 0;
 352 }
 353 static void __exit cpufreq_stats_exit(void)
 354 {
 355         unsigned int cpu;
 356
 357         cpufreq_unregister_notifier(&notifier_policy_block,
 358                         CPUFREQ_POLICY_NOTIFIER);
 359         cpufreq_unregister_notifier(&notifier_trans_block,
 360                         CPUFREQ_TRANSITION_NOTIFIER);
 361         for_each_online_cpu(cpu)
 362                 cpufreq_stats_free_table(cpu);
 363 }
 364
 365 MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
 366 MODULE_DESCRIPTION("Export cpufreq stats via sysfs");
 367 MODULE_LICENSE("GPL");
 368
 369 module_init(cpufreq_stats_init);
 370 module_exit(cpufreq_stats_exit);